This invention relates to a terminal, to which a wire can be connected with a simple processing without the need for removing a sheath of the wire, a structure of connecting the terminal and the wire together, and a terminal producing method.
Further, this invention relates to a piercing terminal for piercing a wire to be connected thereto, and more particularly to a piercing terminal for electrical connection to a wire having a conductor including a plurality of wire elements twisted together into a bundle.
In wire harnesses for an automobile or the like, press-contacting terminals have heretofore been used as terminals to which a wire can be connected with a simple processing without the need for removing a sheath of the wire.
FIG. 22 shows one example of conventional press-contacting terminals and this press-contacting terminal 1 includes a fitting portion 1a for a mating terminal, and a wire connection portion continuous with this fitting portion. In this wire connection portion, press-contacting blades 1e are stamped out of opposite side walls 1c, extending upwardly respectively from opposite side edges of a bottom wall 1b, and are bent inwardly, and a slot 1d is formed between opposed inner edges of each pair of the press-contacting blades, and in the illustrated example, the two (front and rear) pairs of press-contacting blades le are formed. As shown in FIG. 23, the opposed press-contacting blades le of the press-contacting terminal 1 cut a sheath 3a of a wire 3, and are press-contacted with a conductor 3b within the wire in a gripping manner, thus connecting the terminal 1 to the wire 3.
However, in the conventional press-contacting terminal, the press-contacting blades are contacted with the conductor within the wire in gripping relation thereto, and therefore in the case where the wire is thin (that is, the number of wire elements, forming the conductor within the wire, is small, and each wire element is thin), the wire elements are severed by the contact pressure (the load of contact of the press-contacting blades with the conductor), so that the conductor is cut, and in the case where the wire is thick (that is, the number of the wire elements is large), the contact pressure concentrates on the outer wire elements to cut these outer wire elements, so that the pressure of contact of the press-contacting blades decreases, and therefore the contact of the press-contacting blades with the conductor becomes unstable, thus inviting a problem that the contact reliability is lowered.
This invention is made in order to solve the above problems, and an object of the invention is to provide a terminal, to which a wire can be connected with a simple processing and which is excellent in contact reliability, and also to provide a method of producing this terminal.
According to the invention of aspect 10, there is provided a terminal characterized in that a pin, which can pierce a sheath of a wire to contact a conductor within the wire, is formed on a bottom wall of the terminal.
In this invention, the pin, formed on the bottom wall, is caused to pierce the wire, thereby connecting the terminal to the wire, and therefore the cutting of wire elements is less liable to occur as compared with the conventional press-contacting terminal which grips the conductor by the press-contacting blades, and therefore the incomplete contact, caused by the cutting of the wire elements when the wire is thin or thick, can be reduced. And besides, the terminal and the wire can be positively connected together with a simple processing without the need for removing the sheath of the wire.
The invention of aspect 2 is directed to the terminal according to aspect 1, characterized in that side walls are formed on opposite edges of the bottom wall, respectively.
In this invention, the wire connection processing can be effected merely by inserting the wire between the opposite side walls of the terminal without the need for removing the sheath, and the connection processing can be effected utilizing facilities similar to those for the conventional press-contacting terminal. And besides, after the wire is connected, a load is applied to the wire from the opposite side walls to compress the wire, so that the pin contacts the conductor at the proper contact pressure, thereby preventing the wire from being disengaged from the pin.
The invention of aspect 3 is directed to the terminal according to aspect 2, characterized in that a plate, which can be bent to cover the wire, is formed on an upper edge of the side wall.
In this invention, the plate, formed on the upper edge of the side wall, is bent to cover the upper side of the wire, thereby positively preventing the wire from disengagement from the pin.
The invention of aspect 4 is directed to the terminal according to aspect 3, characterized in that a hole for passing the pin therethrough is formed through the plate.
In this invention, the plate is bent to cover the upper side of the wire, and further the distal end portion of the pin is passed through the hole, and by doing so, the wire can be more positively prevented from disengagement from the pin.
The invention of aspect 5 is directed to the terminal according to any one of aspects 2 to 4, characterized in that the side walls or the plates are spread out upwardly to form an opening between distal ends thereof.
In this invention, the upwardly spread-out side walls or the upwardly spread-out plates serve as a receiving port for receiving the wire, and prevent the misregistration of the wire at the time of connecting the wire, and therefore the wire can be smoothly inserted between the side walls.
The invention of aspect 6 is directed to the terminal according to any one of aspects 1 to 5, characterized in that a plurality of pins are formed on the bottom wall.
In this invention, the plurality of pins are formed on the bottom wall, and therefore the area of contact between the terminal and the wire increases, thereby enhancing the contact reliability, and besides the wire is prevented from disengagement from the pins.
According to the invention of aspect 7, there is provided a structure of connecting a terminal and a wire together, characterized in that a pin is formed on a bottom wall of the terminal, and the pin pierces a sheath of the wire to contact a conductor within the wire, and a distal end portion of the pin is bent.
In this invention, the wire is fixed by bending the distal end portion of the pin, and therefore the wire is positively prevented from disengagement from the pin.
According to the invention of aspect 8, there is provided a method of producing a terminal, characterized in that a pin, which can pierce a sheath of a wire to contact a conductor within the wire, is formed on a bottom wall of the terminal, and the pin, which is separate from a base material of the terminal, is joined to the base material of the terminal.
In this invention, the pin is joined to the base material of the terminal, for example, by laser welding or the like, and therefore the pin, made of a material having desired strength, electrical resistance and so on, can be formed in a desired position on the bottom wall, and the terminal of high quality can be produced.
According to the invention of aspect 9, there is provided a method of producing a terminal, characterized in that a pin, which can pierce a sheath of a wire to contact a conductor within the wire, is formed on a bottom wall of the terminal, and the pin is formed integrally with the terminal by raising a stamped-out portion of a base material of the terminal.
In this invention, the pin is formed by stamping the relevant portion out of the base material of the terminal and then by raising it, and therefore the pin can be formed by the method similar to a method of forming a press-contacting blade of a conventional press-contacting terminal, and the facilities for producing the conventional press-contacting terminals can be utilized, and therefore the terminals can be produced at low costs.
Further, it is another object of this invention to provide a piercing terminal of high connection reliability, in which in the processing of an end portion of a wire, having a conductor including a plurality of wire elements twisted together into a bundle, the cutting of the wire elements, forming the conductor, is avoided, and besides this piercing terminal can be used also for a wire of a small diameter.
The above object is achieved by a piercing terminal of the invention (as defined in aspect 10) for connection to an end portion of a wire including a conductor, including a plurality of wire elements twisted together into a bundle, and an insulating covering material covering an outer periphery of the conductor; characterized in that a wire connection portion of a generally U-shaped cross-section for receiving the end portion of the wire is formed by an electrically-conductive sheet; and a piercing portion, which can pierce the insulating covering material of the wire to contact the conductor within the wire, is formed upright on a bottom plate of the wire connection portion, and the piercing portion is formed by stamping a relevant portion out of at least one of left and right side plates of the wire connection portion and by raising the stamped-out portion.
In this piercing terminal, the piercing portion, which can pierce the insulating covering material of the wire to contact the conductor within the wire, is formed upright on the bottom plate of the wire connection portion, and the piercing portion is formed by stamping the relevant portion out of the side plate of the wire connection portion and by raising the stamped-out portion. With this construction, even in the case where the wire connection portion is narrowed so as to receive the wire of a small diameter, the piercing portions can be formed upright on the bottom plate while securing the mechanical strength of the wire connection portion against an external force such as a bending force.
The piercing portion is stamped out of the side plate, and is raised to be formed on the bottom plate, and with this construction the degree of freedom of the design (such as a configuration) of the upstanding piercing portion becomes high. In the construction of the invention, the piercing portion of any of various configurations can be stamped out of the side plate, and can be raised to be formed upright on the bottom plate. And besides, as compared with the type of terminals in which the piercing portion is stamped out of the bottom plate, and is raised, the length of the wire connection portion can be made shorter, so that the terminal can be shortened.
There can be provided such a construction as defined in aspect 11, in which a plurality of the piercing portions are formed upright on the bottom plate, and are arranged in a row in a direction of a length of the wire, and the adjacent piercing portions are stamped out of the different (left and right) side plates, respectively, and are raised. With this construction, even in the case where the plurality of piercing portions are formed upright on the bottom plate so as to increase the areas of contact with the wire, depending on the specification of connection to the wire, the left and right side plates will not much differ in mechanical strength from each other, and therefore will be generally balanced in mechanical strength with each other, since the piercing portions are stamped alternately out of the left and right side plates, and are raised. Therefore, the plurality of upstanding piercing portions can be formed without any problem while securing the sufficient strength of the wire connection portion, and the areas of contact thereof with the conductor of the wire can be increased.
There can be provided such a construction as defined in aspect 12, in which the piercing portion is generally in the form of a flat plate, and is disposed parallel to the direction of the length of the wire. With this construction, when the piercing portion is caused to pierce the wire, the area of contact thereof with the conductor of the wire can be increased, thereby enhancing the connection reliability.
There can be provided such a construction as defined in aspect 13, in which the piercing portion generally in the form of the flat plate is formed on the bottom wall to be a mountain-like shape. With this construction, the piercing portion is wider at its foot portion (serving as its proximal end portion) than at its apex portion, and therefore the upstanding strength is sufficiently high that the piercing portion will not be brought down upon piercing into the wire. Namely, the piercing portion can pierce the wire, and besides the sufficient strength of the piercing portion, extending upright from the bottom plate, can be secured.
There can be provided such a construction as defined in aspect 14, in which the wire can be received and held between the left and right side plates in a compressed manner. With this construction, the pressure of contact between the piercing portion and the conductor (that is, the load of contact with the conductor) after the piercing operation can be increased, thereby enhancing the connection reliability.